Study On The Mechanism Of Quorum Sensing Signaling Molecule AI-2 Inducing Th Cell Differentiation

Objective: To investigate the effects of V.halveyi supernatant and Autoinducer 2(AI-2)on the proliferation and differentiation of Th17/Treg cells isolated from mouse spleen.Method : 1.The chemiluminescence intensity of the quorum-sensing signal molecule AI-2 was measured in different growth cycles,and the growth cycle corresponding to the maximum chemiluminescence intensity of the quorum-sensing signal molecule AI-2 was determined.The sterile supernatant was extracted from Vibrio havierii at this time.2.Preparation of AI-2 solution using DPD precursor(1-(2S)-1,4-dioxaspiro[4.5]dec-2-yl-1,2-propanedione1-(2S)-1,4-dioxonella [4.5] decan-2-yl-1,2-malonone).3.Spleen mononuclear cells were prepared from male BALB/c mice and stimulated with5 g/ml anti-CD28+3ng/ml TGF-β+30ng/ml IL-6 for 72 hours to prepare Th0 cells.The experiment was divided into two groups:(1)Vibrio haversiii supernatant experimental group: the cell culture medium: Vibrio haversiii supernatant(solution volume ratio)=(1:0,9:1,4:1,3:2);(2)AI-2 experimental group: 4 different concentrations of AI-2 solution(0u M,50 u M,100 u M,200 u M)were added respectively.4.The Vibrio haversii experimental group and A-2 experimental group were cultured for 24 h and 48 h respectively,and the proportion of Th17 and Treg cells was detected by flow cytometry.Results: 1.Compared with the absorbance value of OD490 nm and the chemical fluorescence intensity of AI-2 at each time point,the absorbance value of OD490 nm and the chemical fluorescence intensity of AI-2 were the highest at 16 hours of culture.2.The results of flow cytometry showed that the proportion of Th17 cells decreased with the increase of the concentration of supernatant(P<0.05),the proportion of Treg cells increased with the increase of the concentration of supernatant(P<0.05),and the Th17/Treg ratio decreased with the increase of the concentration of supernatant(P<0.05).4.Flow cytometry showed that the proportion of Th17 cells decreased with the increase of the concentration of bacterial supernatant(P<0.05),the proportion of Treg cells increased with the increase of the concentration of bacterial supernatant(P<0.05),and Th17/Treg ratio decreased with the increase of the concentration of bacterial supernatant at 24 and 48 hours.Conclusion: The quorum-sensing signaling molecule AI-2 can inhibit the differentiation of Th0 cells into Th17 cells and promote the differentiation of Th0 cells into Treg cells in the body’s immune activity.